GPS Longevity

My first aviation GPS (a Trimble Flightmate Pro) lasted about 7 years before
the LCD screen started acting wonky.

Then I bought a Lowrance Airmap 100, which has done very well for about 7
years, but seems to be having problems recently on both the internal and
external antennae. Sometimes it goes for a looong time before it can
determine its location. Beyond that, updates are no longer available for
this unit, so if things don't change, I'll probably be in the market for a
GPS.

Which brings to mind the question of how long of a service life do most of
you experience on your handheld GPS's? Do you usually retire them because
someone has marketed a better mousetrap, because the unit is unsupported, or
because the unit no longer works properly?

By the way, does anyone have information about Lowrance putting out an XM
product? At SnF last year, someone who was in a position to know indicated
that Lowrance would probably have an XM aviation GPS available this year. I
prefer Lowrance over Garmin, and am hoping Lowrance will introduce a new
product at SnF....